Search

Calculations of the velocity profile, force, moment and bending moment using a theoretical model are carried out for the three-dimensional “conical-helical” beat of a cilium of Paramecium multimicro-nucleatum. The mean velocity profile obtained by numerical computation is found to be twisted in form: it is inclined at a slight angle to the effective stroke at the top of the cilia sublayer, but twists around with the recovery stroke in the lower part of the sublayer. The force and moment are larger during the fast effective stroke, but over a complete cycle their contributions are approximately zero. Calculations on the bending moments reveals that they are larger during the recovery stage of the beating cycle.

Isochronal annealing of electron irradiated and unirradiated carbon–iron alloys (350 and 700 at ppm carbon), as well as of irradiated high purity iron, has been studied by electrical resistivity measurements in the temperature range from 4.2 to 450 °K. A new recovery stage (3%) is revealed centered at 21 °K in both the alloys and the high purity iron. The presence of carbon in solution suppressed the IE recovery stage (130 °K) while no effect was found on recovery stages below this temperature. This supports the interpretation that irradiation softening found in iron at low temperatures is due to direct effect of self-interstitials. In the temperature range 250 to 300 °K the quenched and irradiated alloy specimens exhibited resistivity increase upon pulse annealing. On the other hand, the as-quenched alloy specimens showed only a simple recovery above 270 °K. A possible explanation for the appearance of this resistivity increase is discussed. Durch Messungen des elektrischen Widerstands wurde die isochrone Ausheilung sowohl von elektronenbestrahlten und unbestrahlten Kohlenstoff-Eisen-Legierungen (350 und 700 At. ppm Kohlenstoff) als auch von bestrahlten hochreinem Eisen im Temperaturbereich von 4,2 bis 450 °K untersucht. Es wurde eine neue Erholungsstufe (3%) bei 21 °K in beiden Legierungen und im reinen Eisen entdeckt. Die Anwesenheit von gelostem Kohlenstoff setzt die IE-Erholungsstufe (130 °K) herab, wahrend unterhalb dieser Temperatur kein Einflus auf die Erholungszustande gefunden wurde. Dies unterstutzt die Interpretation, das die Bestrahlungsentfestigung, die im Eisen bei niedrigen Temperaturen gefunden wird, durch den direkten Einflus von Eigen-Zwischengitterstorstellen verursacht wird. Im Temperaturbereich von 250 bis 300 °K zeigen die abgeschreckten und bestrahlten Legierungsproben eine Widerstandszunahme nach Impulstemperung. Auf der anderen Seite zeigen die Legierungsproben unmittelbar nach der Temperung nur eine einfache Erholung oberhalb 270 °K. Eine mogliche Erklarung fur das Auftreten dieses Widerstandsanstiegs wird diskutiert.

A "geometrical" model is presented for the hexagonal close-packed lattice proposing several principal mechanisms for the displacement of a knocked-on atom. Using the experimentally determined resistivity-change rates of a previous paper and matching families of cross sections computed with this model, we have calculated sets of thresholds energies for displacement in the directions [0001], [10\ifmmode\bar\else\textasciimacron\fi{}14], [1012], [10\ifmmode\bar\else\textasciimacron\fi{}11], and [11\ifmmode\bar\else\textasciimacron\fi{}20] in cobalt, zinc, and cadmium. The correlation between the resistivity-change rates and the displacement cross sections allowed the determination of the Frenkel-pair resistivity per unit concentration in cobalt and zinc: ${\ensuremath{\rho}}_{F}^{\mathrm{Co}}\ensuremath{\approx}\frac{3{\ensuremath{\rho}}_{0\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}}^{\mathrm{Co}}}{\mathrm{at}.%}$, ${\ensuremath{\rho}}_{F}^{\mathrm{Zn}}\ensuremath{\approx}\frac{3.5{\ensuremath{\rho}}_{0\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}}^{\mathrm{Zn}}}{\mathrm{at}.%}$; no definite conclusion for ${\ensuremath{\rho}}_{F}^{\mathrm{Cd}}$ could be made owing to the proximity of a recovery stage. Expressions for the energies needed to pass across one or several open "windows" in the hcp unit cell were derived, including the possibility of focusing collisions in the [11\ifmmode\bar\else\textasciimacron\fi{}20] direction, and compared with the previously calculated threshold energies for displacement in various directions. This comparison permitted the tentative deduction of interatomic potentials of the Born-Mayer type giving as a possible choice: ${U}^{\mathrm{Co}}(\mathrm{eV})=3300{e}^{\ensuremath{-}4.1r(\AA{})}$, ${U}^{\mathrm{Zn}}(\mathrm{eV})=280{e}^{\ensuremath{-}2.5r(\AA{})}$, ${U}^{\mathrm{Cd}}(\mathrm{eV})=300{e}^{\ensuremath{-}2.0r(\AA{})}$.

Electroencephalograms (eeg) were recorded in normal subjects, who breathed gas mixtures containing from six to eleven volume per cent oxygen for five to seven minutes. Changes of eeg were expressed with mean am-plitude and mean period obtained from the recorded brain waves. 1. Under a high degree of oxygen lack, following changes of eeg were observed. Within a minute after the beginning of the gas breathing, small rapid waves appeared, and corresponding to this change, the mean period was temporarily diminished. Two or three minutes later slow large δ-waves appeared in groups, and the mean amplitude and mean period increased rapidly hand in hand. In the final stage of the gas breathing eeg consisted of almost only δ-waves. 2. In oxygen lack of a slighter degree potentials were markedly sup-pressed at an early stage of the gas breathing, and thereafter the mean period increased prior to the mean amplitude. 3. Soon after the cessation of the gas breathing, δ-waves disappeared, but the normal pattern of eeg was not recovered for a long time. Eeg at the recovery stage were found similar to those obtained in mental fatigue.

Results of new resistometric investigations on the ageing after cold-work of an Al-Zn 10% alloy, as well as results of previous experiments on this alloy, are analysed in the light of the main different models advanced for the recovery stage III in Al. A new interesting phenomenon observed in the isothermal ageing after low deformation, namely a slowing down of the initial clustering rate by raising the temperature in the neighbourhood of −50°c, appears explicable only by the vacancy model for stage III.

Simultaneous recordings of the nasal and antral pressures were performed during breathing, sniffing and nose-blowing at 164 antral punctures in 100 patients. Various disturbances in the permeability of the maxillary ostium are described. Model experiments show that the amplitude of the antral respiratory fluctuations is smaller than that of the nasal in the presence of a partial ostial obstruction or with fluid in the ostium or sinus. The ostial resistance can be calculated from the recordings when the ostium opens during sniffing or blowing and when it acts as a valve. A residual positive or negative antral pressure is obtained with a valve-functioning ostium on blowing or sniffing.In chronic sinusitis the ostium resisted the pressures at every puncture during blowing and sniffing. Recordings in acute sinusitis with relatively profuse antral secretion usually gave similar results, while better ostial permeability was sometimes found in the recovery stage.

Skeletal muscle shortens slightly in the early part of an ischaemic period, but tends to lengthen in the later part. The readmission of blood is followed by an immediate shortening of the muscle. The length of the muscle varies irregularly during the fibrillary phase, which occurs between the 2nd and 7th minute in the human limb. The extent of the voluntary contraction, as tested by infrequent single contractile efforts, is hardly affected by ischaemic of 15 minutes' duration. After this time a rapid decline sets in, with the result that the power of voluntary movement disappears almost completely in the course of 25 to 30 minutes, while (diminished) contractile response can be still got from nerve-trunk and from direct muscle-stimulation by single induced shocks, faradic and galvanic currents. The earlier failure of the voluntary effort is not accounted for by the raised threshold referred to below. During ischaemic there is decreased excitability (raised threshold) to single induced shocks and faradic currents, the stimuli being applied to nerve-trunk, motor point, or muscle direct; after ischaemic has lasted for some minutes, there is evidence of increased excitability to galvanic currents. After the re-establishment of the circulation, the full extent of the voluntary contraction is recovered in about 10 to 15 minutes. Decreased excitability to single induced shocks and faradic currents is well-marked, especially with minimal and submaximal stimuli; at the same time the muscle is relatively more excitable to galvanic stimuli. But the characteristic reactions of degeneration are not fully reproduced. During the phase of fibrillary twitchings the response to voluntary and all forms of peripheral stimulation (minimal and submaximal) is depressed, faradic stimulation being least affected; in the later part of this phase there is prolongation of the muscle curve. In the rabbit, ischaemic of a portion of a nerve-trunk of nearly two hours' duration did not abolish conduction or excitability. Likewise the direct excitability of muscle was not lost during ischsemia of over two hours' duration. A muscle, however, will not respond to nerve-trunk stimulation after nearly one hour of ischwemia. This indicates a selective effect of ischaomia on the field of conjunction between nerve and muscle. In animal experiments the results obtained as regards muscular response to electrical stimulation are in substantial agreement with those for man, although the fibrillary phase and lengthening of the muscle#x2010;curve were not seen. The staircase phenomenon, in contractions excited voluntarily or artificially during a period of ischemia, is well#x2010;marked in the early stages; but is absent or of a descending order in the later stages. It is well#x2010;marked in the early post#x2010;ischlumic recovery stage; indefinite during the early part of the fibrillary phase, but present in the subsequent depressive post#x2010;ischwmic period with strong stimuli. While ischamia of under 15 minutes' duration has little effect on the strength of response to a single voluntary effort, it reduces greatly the total amount of work (prior to fatigue) of which a voluntary muscle is capable during a series of active contractions, as compared with the muscle with continuous circulation. The total work differs little when begun at different periods of time in the first 15 minutes of ischaemic. Thereafter the decline in the sum of voluntary work proceeds much more rapidly in the course of the succeeding 10 minutes. Faster rates of voluntary contraction produce more work (up to the fatigue point) than slower rates in experiments carried out shortly after the induction of ischaemic-this is due possibly to the augmenting influence of a rapid series of contractions. I am indebted to Professor MacWilliam for much help and suggestion in the above studies, the expense of which has been assisted by a grant from the Carnegie Trust for the Universities of Scotland.

An inhomogenious deformed state is produced in the cold worked metal. This inhomogenious state must be larger in the high symmetric crystal than the low symmetric one. For example, in the alpha-zirconium of hexagonal closed packed crystal, the homogenity or internal stress which is produced by the cold work, must be larger than in cubic iron crystal and in copper.Thus, if cold worked zirconium were annealed at low temperature or aged at room temperature after cold working, comparatively great size change could be expected, which would be worth while considering the accurate size of zirconium parts of atomic reactors.Twisted zirconium wire specimens of various working degrees were anneald with whole torsion apparatus which was dipped freely hanging in the oil bath. The temperatures of oil bath were 100, 170, and 300°C, After annealing for proper time, the apparatus was picked up and the returning angle was read at the pointer.The regults are as follows:-(1) The strain recovery by low temperature annealing occurres in two stages, the first one is rapid and the second one is slow.(2) The relationship between the logarithmus of annealing time and the strain recovery is linear.(3) The strain recovery of zirconium is greater than that of copper.The process of the recovery at low annealing temperature is expressed by kuhlmann, cottrell's formula. We consider that the inhomogenity owes to the interference of boundaries and the relaxation within grains as considered by Zener.In the heat treatment for the purpose of releasing those internal stress, the proper annealing temperature range is 300-350°C. For this purpose, as high temperature as possible and the first recovery stage are economical.

Serum haptoglobin levels were determined several times during the course of the disease in children with infectious hepatitis. At the onset of uncomplicated acute hepatitis the serum haptoglobin is in the normal range. There is a significant temporary rise in serum haptoglobin during the recovery stage of the disease, after which it returns to normal. The absence of this rise or the fall of serum haptoglobin below normal level are unfavorable prognostic signs, indicating the transition of the disease to the subacute or chronic form.

Twenty five patients with Harada's disease are examined with fluorescein angiography to study on the incidence and the cause of the change in the optic disc. The results obtained are as follows : 1) The fluorescein angiographic finding of the optic disc reveals two kinds of finding: true papilledema (papillitis) and pseudo - papilledema (pseudopapillitis). 2) The fluorescein leakages from the optic disc are demonstrated either from the initial stage or at recovery stage of the disease with relatively high frequency (36 %). 3) It is confirmed that the cause of these fluorescein leakages in the optic disc is closely related with severity of the disease process.From the results obtained, it is pointed out that fluorescein angiographic finding of the optic disc in the Harada's disease is of importance for determination of the severity of the disease process and prognosis.

Annealing experiments on quenched-in vacancies were performed with specially prepared high-purity molybdenum wire. The recovery stage was found to be centred at about 370°C, and the activation energy for the recovery was determined to be (1.62 ± 0.27) eV. The activation energy is tentatively considered to be the activation energy for the migration of single vacancies. With the activation energy, the loss of vacancies during quenching was discussed. The loss at the surface is found to be predominant. Correction for this loss was applied to the previously reported quenched-in resistivity results, and the formation energy of a vacancy was redetermined to be (3.24 ± 0.09) eV. These results are discussed in comparison with data on tungsten.

An plastisch verformten ein- und vielkristallinem Nickel wird mit Hilfe von Dampfungsmessungen (Torsionspendel) der von der Umorientierung der 〈100〉-Vorzugsrichtungen von Ni-Zwischengitteratomen herruhrende Relaxationsprozes untersucht. Die Mesergebnisse sind in vollstandiger Ubereinstimmung mit den theoretischen Voraussagen, insbesondere hinsichtlich der Orientierungsabhangigkeit, der Breite und des Erholungsverhaltens dieses sogenannten Hantelmaximums. Daraus ist zu folgern, das bei Raumtemperatur in verformtem Nickel Einzel-Zwischengitteratome vorhanden sind und das diese in Erholungsstufe III ausheilen. Wahrend in Nickel der untersuchte Relaxationsprozes von der Rotation der Zwischengitteratome herruhrt (Aktivierungsenergie 0,87 eV), scheint der entsprechende Prozes bei Kupfer (Aktivierungsenergie 0,66 eV) mit der Wanderung der Zwischengitteratome verbunden zu sein. The relaxation process due to the re-orientation of the 〈100〉 preferential directions of interstitial Ni atoms is investigated in plastically deformed Ni mono- and polycrystals by means of damping measurements (torsion-pendulum). The results are in complete agreement with the theoretical predictions, especially with respect to the orientation dependence, the width, and the recovery behaviour of this so-called dumb-bell maximum. It is concluded that single interstitial atoms exist in deformed Ni at room temperature and that they anneal in the recovery stage III. In Ni the investigated relaxation process is due to a rotation of the interstitial atoms (with an activation energy of 0.87 eV). The corresponding process in Cu, however, seems to be due to the migration of the interstitial atoms (with an activation energy of 0.66 eV).

The recovery of zirconium of two different purities, cold rolled to 80 % reduction at room temperature, has been followed by means of electrical resistivity measurements at −196° C. In 99.5 % zirconium, recovery proceeds mainly in two stages. The first stage (stage A1) ranging between room temperature and ~ 315° C, is characterized by an activation energy increasing linearly with recovered extra resistivity between 1.00 and 1.85 eV and obeys logarithmic kinetics; this has been attributed to a small scale dislocation rearrangement. The second stage (stage B1), centred at 475° C, is characterized by an activation energy of 2.30 ± 0.25 eV and corresponds to recrystallization. In 99.95 % zirconium, stage B1 is lowered to ~ 325° C and is characterized by an. activation energy of 1.70 ± 0.15 eV . On the other hand, the first recovery stage begins only above 100° C and is characterized by a constant activation energy of 1.35 ± 0.05 eV (stage A2). This may be reasonably attributed to point defect annealing, which probably occurs also in 99.5 % zirconium, but remains unresolved under the continuous background due to dislocation re-arrangement.

The isochronal recovery of deformed polycrystalline Al was measured from 4 to 300 °K by means of residual electrical resistivity measurements. A well-defined recovery stage was observed between 60 and 100 °K (stage IIA); it has also been observed after neutron irradiation, but not after electron irradiation (Sosin 1963). This stage was enhanced by increasing the deformation or introducing quenched-in vacancies, and was suppressed by impurity atoms. These results can be explained by di-interstitial migration. The recovery below 60 °K (stage I) amounted to approximately 5%, and was independent of impurity content or degree of deformation. Both stage I and stage IIA recovery were greatly increased by a prior deformation and low-temperature anneal. A similar increase was observed for Au. This enhancement was attributed to a change in deformation mechanism because of dislocation pinning, which resulted in the formation of a preponderance of interstitial defects.

The recovery of 99·996% pure nickel deformed at low temperatures has been investigated in the range 25° to 350°c. Stage IV recovery previously reported to occur at 260°c was not observed but stage III, centred at 90°c, was found. Additions of up to 0·50 at. % iron or 0·46 at. % silicon produced only slight changes in the recovery spectrum. Addition of 0·04 at. % gold produced a very small recovery stage at about 230°c, and 0·51 at. % gold made separate recovery stages indistinguishable. Addition of 0·04 at. % carbon caused a recovery stage to appear at 260°c, and this stage increased in magnitude with increasing carbon content. The results suggest that stage IV recovery in deformed nickel could be caused by the migration of carbon atoms and the stage in which free migration of single vacancies occurs has not been positively identified.

The recovery of the electrical resistivity of polycrystalline 99.999% Au, Cu and Al, deformed at liquid helium temperature by elongation, was studied in the temperature range of 4.2° to 200°K. Initial recovery was followed in general by the large recovery stage for the three metals. The initial recovery stage was attributable to the dislocation rearrangement. The latter was considered to be due to annihilation of interstitial type defects. The results are discussed on the basis of current theories.

The temperature region of recovery of four aluminium alloys containing 2.4, 3.7, 8.3 and 11.9 wt% Al 2 O 3 is given in dependence of the alumina content and the degree of deformation. It is found that the alloys containing 8.3 and 11.9 wt% Al 2 O 3 recover on annealing one hour below or just at the melting point of pure aluminium. The absolute increase of Vickers hardness due to deformation with respect to the recovered state is independent of the Al 2 O 3 content and as high as in strongly deformed aluminium. The recovery of the electrical resistivity above the temperature of liquid nitrogen was investigated and in recovery stage III two activation energies were found. These activation energies are attributed to divacancy (0.35 eV) and to interstitial migration (0.58 eV), by comparison with results known from pure aluminium.

Die Erholung reinen Eisens nach Kaltverformung oder Neutronenbestrahlung wurde durch die Messung der gespeicherten Energie zwischen 20 und 450 °C verfolgt. In beiden Fallen wurde eine Erholungsstufe im gleichen Temperaturgebiet gefunden. Auf Grund der experimentellen Ergebnisse und eines Vergleiches mit anderen kubisch raumzentrierten Metallen wird die Natur der ausheilenden Defekte diskutiert. The recovery of cold-worked or neutron-irradiated pure iron is investigated using storedenergy measurements over the temperature range 20 to 450 °C. In both cases a single recovery stage is found, which lies in the same temperature range for both types of treatment. On the basis of the experimental results, and a comparison with other b.c.c. metals, the nature of the defects which anneal out in the observed recovery stage is discussed.

— The activity of arylsulphatase A (EC 3.1.6.1) was measured in several brain sub cellular fractions during experimental allergic encephalomyelitis in rats. In the acute stage there was a slight but significant increase in the brain homogenate in comparison to that from control animals. The alteration appeared to be localized in a subcellular fraction con stituted mainly by myelin fragments. The arylsulphatase A activity returned to the control level in the recovery stage.

Eighty-seven University of North Carolina students who had clinical and serologic evidence of infection with type A influenza viruses related to Asian strains were studied electrocardiographically, both during the illness and after recovery. The electrocardiograms were evaluated by comparison with those of a control series similar in age, sex, and social distribution. Extracardiac factors were taken into consideration. Twelve electrocardiograms were considered to be abnormal because of S-T segment deviation, depression of T waves, and auricular arrhythmias. Four of these abnormalities, including all the arrhythmias, occurred in the recovery stage. It was concluded that although these changes were minor, they could have been caused by myocarditis due to infection with influenza virus.

1. Changes in the cerebral functional state were studied electroencephalographically in fatigue induced by forced swimming of 13 rats.2. The characteristic changes of the EEG's in fatigued rats were the suppression of the basic waves and increase of the small fast waves, which indicate an enhanced state of cerebral excitatory level and considered to be an excited period of fatigue (Type 1).3. Both the average frequency and amplitude increased in one rat in the fatigued state, and indicate a higher excitatory level than type 1 (Type 2).4. Slow waves appeared in the recovery stage in one rat, and indicated a drowsy state or lowered level in cerebral excitation and is considered to be an inhibited state of fatigue (Type 3).5. It has already been shown by us that the excited period was generally followed by an inhibited period in mental fatigue, but only an excited state of the brain was found in somatic fatigue, even though the animal was thought to be extremely fatigued, except for one case in the recovery stage.

The vestibule-ocular and vestibulo-vegetative reflexes were polygraphically studied on two patients with Meniere's disease in whom unilateral labyrinthotomies had been carried out.Electroencephalogram, electronystagmogram, plethysmogram, galvanic skin reaction, electrocard iogram and respiration were simultaneously recorded in the patients recovering from general anest hesia and for 52 hours after the operation.The results obtained were as follows :1. Spontaneous nystagmus in the recovery stage from the anesthetic condition was towards the unoperated side, and gaze nystagmus, also remained.2. In the awakened condition from anesthsia, spontaneous nystagmus were more frequently recognized in eyes covered or closed than in eyes opened.3. During natural sleeping condition, spontaneous nystagmus and some vegetative phenomenawere extremely suppressed.

The transverse magnetoresistance of annealed and of plastically deformed wires of copper, silver and gold was measured at 20°K and 14°K. When the results are plotted in a Kohler diagram, the deformed material yields a curve which is in general shifted with respect to the curve for the annealed metal. This shift is shown to be temperature dependent; both positive and negative shifts have been found. In many cases recovery at temperatures below 150–200°C only has a small influence on the position of the curve; it returns to its original position, however, upon annealing at sufficiently high temperatures. We therefore assume that the shift is caused by the dislocations present in the deformed metal. In silver the recovery stage at −120°C causes an additional shift, which seems to be independent of the temperature in the region investigated; this effect also disappears upon annealing. Probably the shift can be explained by considering the anisotropic scattering of the conduction electrons by dislocations; a satisfactory theory, in particular concerning the temperature dependence, has not yet been found, however.

Myocardial performance was evaluated in rhesus monkeys after endotoxin shock, and the responses to fluid loading with colloid measured in both anesthetized control and experimental groups. Minute work and cardiac output (CO) were decreased in five monkeys after six hours endotoxin to levels significantly below control values. Infusing colloid to a mean left ventricular end-diastolic pressure (LVEDP) of 12-15 mm Hg increased both CO and minute work significantly but they remained one-half that of the control group of four primates after fluid loading. Improved cardiac performance persisted after infusion through a 30-minute recovery stage when LVEDP returned to normal. Simultaneous pulmonary arterial wedge (PAW) pressures showed some correlation with LVEDP reading up to six mm Hg, but above that level the PAW underestimated the LVEDP by 3-6 mm Hg. Microscopic study showed that fluid loading produced comparable pulmonary edema in both groups, but endotoxin produced ultrastructural capillary lesions.

— The content of cerebrosides, sulphatides, gangliosides, cholesterol and phospholipids was evaluated in the brain and spinal cord of rats during the acute and recovery stages of experimental allergic encephalomyelitis (EAE). During the acute stage there was a significant decrease of sulphatides and gangliosides in spinal cord; in brain, only sulphatides were diminished. In the recovery stage, cerebrosides and gangliosides were decreased in the brain, whereas the lipid content of the spinal cord was similar to that in control animals. Cholesterol esters were detected in the brain and spinal cord during both periods. The results show that the changes are not the same for brain and spinal cord during the acute and recovery stages and that glycosphingolipids from either white or grey matter seem to be preferentially altered.

High purity polycrystalline magnesium samples near 4.7°K that are irradiated with 0.4 MeV electrons give an annealing behavior which is not characteristic of a simple kinetic process. It is shown that one can experimentally use a combined isothermal and isochronal annealing procedure to obtain partial resolution of the recovery data.

It is shown that the experimental data on lead permit an unambiguous assignment of recovery stage III to the migration of self-interstitials and of recovery stage IV to monovacancy migration.

The 175°K recovery stage observed in irradiated high resistivity p-type silicon is not affected by the presence of a high concentration of oxygen, contradicting the thought that the migration of the neutral vacancy is responsible.

Excerpt Various investigators have found that following a transitory stage of hypo- or avitaminemia-A at the height of the disease the blood vitamin A level rises in the convalescent stage to highe...